New data indicate HSV seronegative women have the high estrisk of HSV transmission to the neonate and viral shedding at delivery has a (R.R. >300) for HSV transmission suggesting that interventions should be directed at: 1) the pregnant woman who acquires genital HSV near term and 2) the HSV-2 sero positive woman who reactivates HSV at the time of delivery,who while less likely to transmit, may have morbidity associated with abdominal delivery. SpecificAim 1 evaluates the acceptance of type specific HSV serologic testing in pregnancy and its effect on sexual behavior at the end of pregnancy. Two clinical trials are proposed: a randomized clinical trial of antenatal versus post-partum testing for HSV type-specific antibodies and a trial to evaluate the effect of HSV serologic testing of pregnant women alone vs. pregnant women and their partnerson sexual behavior in 3rd trimester of pregnancy. Hypothesis: women identified as susceptible Ito HSV-1 or HSV-2 will have reduced unprotected coital and unprotected oral-genital activity; knowledge of partners status will lead to further decrease in risky sexual activity. Specific Aim 2 will define the efficacy of short course acyclovir therapy in prevention of viral shedding at delivery among HSV-2 seropositive women. Specific Aim 3 is aimed at development, testing and field implementation of a rapid PCR assay to detect Igenital HSV shedding in women at delivery. Hypothesis:Testing for HSV DNA in genital secretions in labor is an accurate method for identifying women at risk for transmission of herpes to the neonate. Specific Aim 4 will use the results of the proposed studies to perform a decision, cost effectiveness, and utility analyses of various approaches to prevention of neonatal herpes. The strategies for evaluation will include serologici testing, cesarean deliveries, acyclovir treatment and rapid HSV DNA PCR; outcomes will include neonatal herpes, maternal morbidity from cesarean section, and women's preferences. The results from these studies will allow for development of recommendations to decrease the incidence of neonatal herpes.